The embodiments disclosed hereinafter generally relate to hinged surfaces on the trailing edge of airfoils of a fixed-wing aircraft, such as wings, flight control surfaces (e.g., flaps), and horizontal stabilizers. In particular, the embodiments disclosed herein relate to methods for actuating split flaps hingedly mounted to such airfoils.
A split flap is a hinged plate which forms a portion of an airfoil. A split flap provides aerodynamic advantages to an aircraft, but its small scale (typically 1-3% of chord) and location at the extreme trailing edge create difficulties.
It is known to actuate a split flap by means of a complicated mechanical linkage, typically with some form of external hinge or actuation. External hinges or actuation produce extra drag. Complex mechanical linkages involve high part counts, leading to additional cost and weight. The discrete mechanical supports may be more subject to flutter, and a linkage will be susceptible to jamming. Furthermore, actuation of the split flap at discrete points (such as a typical mechanical linkage) is difficult due to the very low stiffness of the small thin split flap, which may increase the risk of the split flap buzzing or fluttering. This forces actuation at many points.
There is a need for systems and methods for actuating split flaps which eliminate extra drag, reduce cost and weight, and lessen flutter and jamming concerns.